To give an example, when a package box is constructed with corrugated cardboard, a subject to be packed is placed in a box body, and then flaps of the package box are applied with an adhesive, such as a hot-melt adhesive, with which the flaps adhere to each other with one over the other to close the package box. To do this, it is necessary that the flaps are reliably adhered to each other with the adhesive.
There are some methods for indirectly determining the adhesion in conjunction with a conventional adhesion inspection apparatus. One such adhesion inspection apparatus detects, for example, an amount of applied adhesive, a temperature of the adhesive, a position and an extent of the application, etc., with use of a camera or an infrared sensor so as to estimate the adhesion.
In addition, as a technique to inspect the adhesion directly, a defective sealing inspecting device for a package box has been disclosed (see Japanese Patent Public disclosure No. 2005-104568). The defective sealing inspecting device has: a lid sucking path La, including a lid sucking tool 31 arranged along a box conveying path; a lid sucking tool transfer device 30 making a circular movement along a lid lifting path Lb, disposed following to the lid sucking path La and out from the box conveying path; and a lid detection sensor 50 for detecting a top surface of a lid 3 that has been peeled away from a box body 2 and lifted up by a lifting force exerted on the lid 3 from the lid sucking tool 31 disposed in the lid lifting path Lb. When such a sealing inspecting device is used, if the lid 3 is in a defective adhesion condition, the lid 3 would be separated from the box 2 and lifted up, and thus lifted-up lid 3 is then detected by a detection device, such as an optical sensor, ultimately enabling the inspection of the defective sealing (adhesion) condition.